Human periodontal disease is a chronic condition that results from bacterial infection of the gingival and the associated inflammatory response. Recent studies estimate that between 35 to 45% of adults in the US have chronic periodontitis, with up to 90% having some form of periodontal disease. In addition to pain, discomfort, and tooth and oral bone damage, periodontal disease has been associated with an increased risk of systemic complications such as coronary heart disease. The primary etiologic agent of periodontitis, Poryphyromonas gingivalis, is closely associated with the onset of periodontal disease. This bacterium, along with the other major cohabitants of the """"""""red complex"""""""" (Treponema denticola and Tannerella forsythensis), is sequestered as a biofilm in plaque or tartar during infection. Delivering therapeutic doses of antibiotics or anti-inflammatory agents over a sustained period of time is difficult and there are major clinical problems in management of this disease. ? ? Destruction of the gingival tissue in periodontitis is mediated in part by host- and microbe-derived protein- degrading enzymes called proteases. The long-term goal of this proposal is to develop a therapeutic agent that gives sustained delivery of a cell protective compound to the gingival pocket. This compound is a novel inhibitor of microbial and inflammatory proteases from a class of """"""""Protector Peptides"""""""" characterized by ECI. When applied to gingival tissue, possibly in combination with an antimicrobial, this agent will protect tissue from further enzymatic damage, reduce the bacterial load, and aid in the resumption of healing. ECI has previously demonstrated that this compound, called heat gamma (HG), is an effective inhibitor of proteases produced by P. gingivalis and host matrix metalloproteases in vitro. HG also protected epithelial cells from bacteria-induced cell damage in a tissue culture model of infection. In this Phase I proposal, the activity of HG delivered on microbeads will be examined in feasibility studies for the final treatment formulation in Phase II. This formulation will consist of HG peptide incorporated into biodegradable hyaluronan microbeads that will be injected into the gingival pocket to provide sustained HG delivery. The Phase I objectives are to show that HG attached to microbeads can inhibit bacterial proteases from the three red complex pathogens in vitro and to examine their effect on a P. gingivalis biofilm (Aim 1). The next objective is to demonstrate the ability of HG microbeads to prevent cell death of gingival fibroblasts after P. gingivalis infection (Aim 2). Lastly, a mouse chamber model will be used to assess the ability of HG delivered on beads to reduce P. gingivalis virulence, viability, and the host inflammatory response in vivo (Aim 3). ? ? ?
| Luan, Xianghong; Walker, Cameron; Dangaria, Smit et al. (2009) The mosasaur tooth attachment apparatus as paradigm for the evolution of the gnathostome periodontium. Evol Dev 11:247-59 |
